<template>
  <div class="area" v-if="cityInfo" ref="area_scroll">
    <div class="scroll_wrap">
      <!-- 热门城市 -->
      <div class="hot-wrap citylist">
        <div class="title">热门城市</div>
        <ul>
          <li v-for="(item, index) in cityInfo.hotCities" :key="index" @click="$emit('selectCity', item)">{{ item.name }}</li>
        </ul>
      </div>

      <!-- 所有城市 -->
      <div class="ity_wrap">
        <!-- 循环按字母排序的 key -->
        <div class="city_content citylist" v-for="(key, index) in keys" :key="index">
          <div class="title">{{ item }}</div>
          <!-- 根据字母 key 展示城市名 -->
          <ul>
            <li v-for="(item, index) in cityInfo[key]" :key="index"  @click="$emit('selectCity', item)">{{ item.name }}</li>
          </ul>
        </div>
      </div>
    </div>

    <div class="area_keys">
      <ul>
        <li @click="selectKey(0)">#</li>
        <li @click="selectKey(index+1)" v-for="(item, index) in keys" :key="index">{{ item }}</li>
      </ul>
    </div>
  </div>
</template>

<script>
import BScroll from 'better-scroll'

export default {
  name: 'alphbet',
  data () {
    return {
      scroll: null
    }
  },
  props: {
    cityInfo: Object,
    keys: Array
  },
  methods: {
    initScroll () {
      this.scroll = new BScroll(this.$refs.area_scroll, {
        click: true
      })
    },
    selectKey (index) {
      const cityList = this.$refs.area_scroll.getElementsByClassName('citylist')
      // 根据下标，滚动到相对应的元素上
      let el = cityList(index)
      // 滚动到对应的位置上
      this.scroll.scrollElement(el, 250)
    }
  }
}
</script>

<style scoped>
.area {
  margin-top: 10px;
  box-sizing: border-box;
  padding: 0 16px;
  background: #fff;
  height: calc(100% - 65px);
  overflow: hidden;
}
.scroll_wrap {
  background: #fff;
  overflow: auto;
}
.title {
  color: #aaa;
  padding: 15px 0;
}
.hot_city {
  padding: 0 16px;
  display: flex;
  flex-direction: row;
  flex-wrap: wrap;
}
.hot_city li {
  width: 30%;
  background: #f1f1f1;
  margin: 0 10px 10px 0;
  text-align: center;
  padding: 10px;
  box-sizing: border-box;
}
.city_content li {
  padding: 10px;
  border-bottom: 1px solid #eee;
}
.area_keys {
  position: fixed;
  right: 0;
  top: 25%;
  color: #aaa;
  font-size: 12px;
  line-height: 1.4;
  text-align: center;
  padding: 0 5px;
}
</style>
